master a8b8744: set-face-font doc string update

[Lars Ingebrigtsen]

branch: master
commit a8b87446656af0395864b7aaa697a4e04bcc1218
Author: Lars Ingebrigtsen <address@hidden>
Commit: Lars Ingebrigtsen <address@hidden>

    set-face-font doc string update
    
    * lisp/faces.el (set-face-font): Mention what the string formats
    are (bug#14647).
---
 lisp/faces.el | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lisp/faces.el b/lisp/faces.el
index 2779197..75753ec 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -888,6 +888,10 @@ Use `set-face-attribute' for finer control of font weight 
and slant."
 
 (defun set-face-font (face font &optional frame)
   "Change font-related attributes of FACE to those of FONT (a string).
+The format of the font varies based on the font system in used,
+but it can commonly be an X logical font description (XLFD)
+string, or a simpler XFD string like \"courier:size=10\".
+
 FRAME nil or not specified means change face on all frames.
 This sets the attributes `:family', `:foundry', `:width',
 `:height', `:weight', and `:slant'.  When called interactively,